Collapsible tube closure and sealing means



D. c. MADDUX COLLAPSIBLE TUBE CLOSURE AND SEALING MEANS Filed July 23, 1957 Aug. 2, 1960 Tia. 24 db -7 Z5 2 $7 24 INVENT OR flu/l/vf C Manx/X Wa /M United States PatentOfice Duane C. Maddux, 3016 W. Verdugo Ave., Burbank, Calif.

Filed July 23, 1951, Ser. No. 673,674 2 Claims. Cl. 222-92 The invention described herein relates to the sealing of collapsible thin-walled tubular containers.

The invention is directed particularly to the sealing of the sides of the passage of the tube to the dispensing opening and the providing of a removable seal across the dispensing opening. 1 K Another aspect of the invention is the means and method for sealing the permanently closed end of the tubular container.

The invention is particularly applicable to the closure means described in my Patent No. 2,715,479, issued August 16, 1955, and in my co-pending application Serial No. 599,998 filed July 25, 1956, entitled Collapsible Tube Dispensing Opening Seal, now abandoned.

In the closure means described in the aforementioned patent and application, the contents of the tubular container are sealed from the outer atmosphere by the pressure of jaw members pressing against opposite sides of the walls of the container forming the dispensing passage. On the application of pressure to the contents of the container, the jaw members are spread and the pressure of the jaw members relieved so that the contents may extrude through the passage and out of the container. It is desirable to seal the dispensing opening to prevent the discharge of the material on the accidental application of pressure to the tubular member during shipment and display of the container prior to the sale to the customer.

The main object of the invention is to maintain the walls of the dispensing opening even, so that a seal is formed by the pressure of the jaw members.

Another object of the invention is to provide a removable seal across the dispensing end of the discharge passage.

A further object of this invention is to provide an inexpensive means for sealing the closed end of the tubular container so that the material does not discharge therethrough.

Other objects will become apparent from the following description taken in connection with the drawings, in which Fig. 1 is a side elevation of a collapsible tube, having a closure means ready for use.

Fig. 2. shows a sectional front view taken along lines 2-2 of Fig. 1.

Fig. 3 is a plan view of the blank from which the glosure is formed.

Fig. 4 is a sectional view of the closure means taken along lines 4-4 of Fig. 1.

Fig. 5 is a plan view of the tubular container without the closure means.

Fig. 6 is a side elevation of a collapsible tube having a closure means and a removable sealing means on the end thereof.

Fig. 7 is a sectional view taken along lines 7-7 of Fig. 6.

Patented Aug. 2., 1960 Figs. 8 and 9 are views of the sealing of the permanently closed end of the tube.

The container 10 is tubular in form and is made with thin flexible walls for containing material which can be extruded from the container on application of pressure to the walls of the container. The end 11 is permanently sealed by a method later herein described, and the other end is formed to provide a closable discharge passage by means of a closure device. The container is made of a waxy, resilient plastic sheet metal such as polyethylene. The container is normally cylindrical in shape. However, at each end it is tapered to form opposing walls. The closed end has walls 12 and 13, and the discharge end has generally opposing walls 14 and 15. The walls are generally co-extensive with one another and have tabs 16 and 17 with edges 18 and 19. The tabs 16 and17 have lateral edges 20 and 21 which form the sides of the dispensing opening through which the material is discharged. The side tab edges 20 and 21 on each side of the tab are welded together to permanently seal the end of the tube along these edges. The end side edges 22 and 23 are also welded together to form a permanent seal so that the discharge end of the tubular member is open along the end tab edges 18 and 19. These edges are sealed by a thin strip 24 of polyethylene placed over the end tab edges 18 and 19 and heat sealed to close the discharge opening. The strip 24 extends from the tab to provide a grip 25 for tearing the strip from the end of the tab, so that the material may be extruded.

The strip 24 is sealed on the tab subsequent to the positioning of the closure means 26 on the end of the tube. The closure means is of the type described in the aforementioned patent and is preferably formed from a single piece of resilient sheet metal in two matching parts 46 and 47 which are folded about a center line to form edges 48 and 49 with the opening 27 therebetween through which the tab extends. The panels 28 and 29 are pressed against the end of the tube to secure the closure means on the end of the tube. The center of the closure means is cut away to form the opening 27 and the openings 30 and 31 on opposite sides of the container. The panels 28 are connected by a side bar 32 curved in a fiat arc to permit passage of material between it and the side bar 33 connecting the panels 29. Jaw portions 34 and 35 are provided with parallel clamping portions 36 and 37 engaging the walls of the tube. The jaws 34 and 35 are secured to the side bars by means of the stems 38 and 39 at the midpoint of the side bars. The jaw members extend at an angle to the stems, to transmit a uniform pressure to the clamping members under the resilient pressure of the stems.

The walls of the container forming the dispensing passage should preferably be flat and taut so that the jaw members can force the walls of the passage together across the dispensing passage, to provide a continuous seal. In this invention, the closure means maintains the walls of the passage even and separates on the application of pressure to the body of the tube. The panels 28 are provided with edges 40 turned at an angle to cooperate with edges 41 on panels 29 to press into the side of the flexible tube and hold the plastic walls between the panels. The walls of the discharge passage are pulled even. As illustrated in Fig. 4, the walls are parallel and in continuous contact across the stated discharge passage 50. The turned edges 40 and 41 extend longitudinally to the pressure applying portions of the jaw members. The turned edges apply pressure to the tube walls in advance of the pressure of the side panels 28 and 29 and tend to press into the walls of the tube.

to prevent the forcing of the plastic material from between the panels 28 and 29 into the area between the panels through which the material is discharged. This maintainsthe walls of the discharge passage smooth and even and in close, flat relation, so that the jaw members, on pressing againstthe walls of the tube, will provide a :uniformseal across the discharge passage.

The closure means 26 and the strip 24 are placed on the empty plastic tube. The tube is then retained in an upright position and filled with the desired contents. The permanently sealed end 11 is open, and in the final step, the end of the tube is heated and sealed to permanently close this end of the tube; A mandrel 42 is inserted in the end of the tube to heat the wall of the tube along a depth suificient to provide a wide sealing surface. The heat of the mandrel renders the inner surface of the wall soft so that on pressing the surfaces together, a continuous and complete seal is formed. The mandrel 42 comprises a solid metal of high heat conductivity, such as copper or aluminum, and has a bore for containing a heating element 43. The heating element 43 is preferably an electrical resistance connected to an electrical current source for heating purposes. The mandrel is held in the end of the tube for a sufiicient length of time to soften the thermoplastic material. The mandrel is removed and the softened material is pressed together by sealing jaws 44 and 45. These'jaws may be located at the heating position of the tube. of the mandrel and the timing of the application of the heat is synchronized with the closing of the jaws. The mandrel is inserted in the end of the tube for the heating period and then removed. The jaws then close to press the ends together. However it is preferable that the heating and sealing step are performed at different stations. The filled tube is moved in position for softening by the heated mandrel, and at the end of the heat- The movement 1. A collapsible container comprising a flexible tubular member of thermoplastic material for containing a soft, extrudible material, closure means secured to one end of said container to form the member in a generally fiat ellipsoidal shape with opposing walls, to form a slit-like passage between said walls for extruding material from said container, said closure means having a pair of opposite jaws with means for pressing said jaws against said walls to close said slit-like passage and permit the opening of said passage on pressing the soft extrudible material in the container, said closure means having a pair of panels on opposite sides of said passage pressing said walls together to seal a portion of the end of the tube and forming the discharge passage therethrough, said panels having inwardly turned edges extending along the side of said panels longitudinally to said passage to retain between the panels the flexible thermoplastic material pressed on clampingof the panels, said walls between said inwardly turnededges being taut to form smooth, even. inner facing sealing surfaces forming a sealing area at the discharge end of the passage and the jaws pressing against the taut wall portions to form a continuous uninterrupted seal along said inner surfaces to prevent the entrance of air or other contaminants within said container, thereby protecting the contents of the container. A

2.-A collapsible container as set forth in claim 1, wherein said tubular member has tabs extending from said walls and forming end surfaces spaced from the jaws, a detachable strip fastened to said end surfaces to seal the end of the discharge passage against accidental discharge.

I claim:

Brown Dec. 22, 1953 

